Reconstruction techniques preparing jaws for fixed dentures placement

Dental implantation is a widespread method of dental arch reconstruction. Alveolar bone quantity in implantation area is crucial for proper implant placement. The paper presents author's experience in alveolar bone reconstruction with mandibular autografts, bone height reconstruction with parietal partial thickness grafts, as well as jaw defects reconstruction with microvascular flaps with subsequent implantation.     

Anorganic porous bovine-derived bone mineral (Bio-Oss) and ePTFE membrane in the treatment of peri-implantitis in cynomolgus monkeys

The purpose of the present study was to evaluate the effect of anorganic porous bovine-derived bone mineral (Bio-Oss) and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was induced during a period of 9-18 months. Surgical treatment involving Bio-Oss+membrane, Bio-Oss, membrane, or a conventional flap procedure (control) only was carried out. The animals were sacrificed six months after treatment. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology demonstrated healthy peri-implant tissue irrespective of the applied surgical procedure. However, the amount of re-osseointegration and the total amount of bone (Bio-Oss and regenerated bone) were significantly higher in defects treated with membrane-covered Bio-Oss as compared with the other three treatment procedures. A mean bone-to-implant contact of 36% was obtained within defects treated with membrane-covered Bio-Oss. The corresponding values for the three other treatment procedures were 13-23%. The Bio-Oss particles were in general highly integrated within the regenerated bone, but the particles in the occlusal part of the defects were entirely surrounded by connective tissue irrespective of membrane coverage. The present study demonstrates that surgical treatment involving Bio-Oss covered by an ePTFE membrane is a useful treatment modality of experimental peri-implantitis around implants with a TPS surface in cynomolgus monkeys. However, the treatment outcome is not as encouraging as seen with membrane-covered autogenous bone graft particles documented in a study with same experimental design.     

Clinical evaluation of freeze-dried block allografts for alveolar ridge augmentation: a case series

Various grafting materials have been used in guided bone regeneration procedures to augment alveolar ridges deficient in horizontal or vertical dimensions or both. Autogenous block grafts from intraoral and extraoral sites have been used for ridge augmentation with encouraging results. However, the risk of vascular and neurologic injury at the donor site as well as postoperative patient morbidity have been reported following these surgical procedures. The use of a cancellous block allograft could be one alternative to avoid potential donor site complications. Five deficient alveolar ridges in three patients were each grafted with a freeze-dried cancellous block allograft and a resorbable barrier membrane. Ridge measurements taken at baseline, graft placement, and a 6-month reentry surgery demonstrated an increase in alveolar ridge width from 2 to 4 mm. These gains in ridge width compare favorably with other guided bone regeneration studies, suggesting that a freeze-dried cancellous block allograft in conjunction with a resorbable membrane may be an acceptable alternative to the autogenous block graft in the treatment of compromised alveolar ridge deficiencies.     

Histomorphometric analysis of rat alveolar wound healing with hydroxyapatite alone or associated to BMPs

Several materials and techniques have been proposed to improve alveolar wound healing and decrease loss of bone height and thickness that normally follow dental extraction. The objective of this research was the histologic analysis of bone morphogenetic proteins implanted into dental alveoli of rats after extraction. A total of 45 adult male Wistar rats were divided into three groups of 15 animals each: control (no treatment), implanted with pure hydroxyapatite (HA, 3 mg) and implanted with hydroxyapatite plus bone morphogenetic proteins (HA/BMPs, 3 mg). Five animals from each group were sacrificed at 7, 21 and 42 days after extraction for the histometric analyses of the osteoconductive potential of hydroxyapatite associated or not with BMPs. After dissection, fixation, decalcification and serial microtomy of 6-micron thick sections, the samples were stained with hematoxylin-eosin for histologic and histometric analyses. Both HA and HA/BMPs caused a delay in wound healing compared to control animals, evaluated by the percentage of bone tissue in the alveoli. The treatment with HA/BMPs had the greatest delay at 21 days, even though it produced values similar to the control group at 42 days. The materials did not improve alveolar repair in the normal period of wound healing and the association of HA/BMPs did not have osteoconductive properties with granulated hydroxyapatite as the vehicle.     

Kieferhöhlenuntersuchung nach Sinusbodenelevation kombiniert mit autologer Onlay-Osteoplastik

Background. Complication rates after sinus floor augmentation of up to 10% are mentioned in literature, often when heterologous bone implants are used. The aim of our retrospective study was to determine the complication rate involving the maxillary sinus of patients treated with autologous spongiosa. Patients and methods. In 46 patients with an absolute maxillary atrophy (61% female, 39% male, mean age 49 years), a sinus floor augmentation, if necessary combined with an onlay bone graft of the iliac crest, was performed. Implants (Brånemark) were placed in a two-stage procedure after 3–6 months. Prior to surgery, a panoramic film was made for diagnosis and treatment planning; in addition, a sinus X-ray was taken when disease of the maxillary sinus was suspected. Panoramic radiography was routinely taken after surgery. A clinical and radiological follow-up examination was performed after 6–12 months, and the patients answered a questionnaire. This study also included evaluation of operation reports and case histories. Ultrasound as well as magnetic resonance imaging to prevent radiation exposure were performed additionally. Results. In spite of perforation of the maxillary sinus mucosa in about 25%, removal of the bone graft due to inflammation was not necessary. A transient sinusitis developed in 2%. The implant loss rate (3 out of 154) may be called small. Discussion. Even though alternative heterologous graft materials exist, maxillary sinus floor elevation with autologous bone graft is still a safe option. Changes of the maxillary sinus are detectable in a small percentage, relatively often due to preexisting unrecognized or subclinical diseases of the maxillary sinus. Magnetic resonance imaging is, in spite of the high financial and technical effort required, a serious alternative to computed tomography. The combination of autologous bone graft with calcium phosphate ceramics, platelet-rich plasma, or synthetic bone growth factors should be tested as an alternative treatment method.     

Bioabsorbable materials for guided bone regeneration prior to implant placement and 7-year follow-up: report of 14 cases

BACKGROUND: The purpose of the present study was to evaluate the efficacy of a guided bone regeneration (GBR) procedure prior to implant placement and the long-term outcome of the inserted implants. METHODS: Prior to dental implant placement, GBR procedure was performed on 14 patients (mean age 48 years) using a synthetic hydroxyapatite (HA) spacer under a collagen membrane. After a mean healing period of 8 months, bone biopsies were obtained during the placement of 14 implants. The specimens were processed for histology without demineralization in order to assess bone quality and quantity of the regenerated bone. RESULTS: Both the bone density and the resorption degree of HA particles were relatively varied between samples. The different phenotypes of osteoclasts and multinucleated giant cells and the individual host response could partially explain the unpredictable results in terms of bone remodeling and biomaterial resorption. However, the presence of HA particles in the regenerated bone had no influence on the osseointegration of implants presenting a success rate of 86% after a 7-year observation period. CONCLUSIONS: These results confirm the possibility of regenerating bone by means of bioabsorbable materials, assuring at the same time the long-term success for implants inserted in regenerated sites.     

Delayed iliac abscess as an unusual complication of an iliac bone graft in an orthognathic case

The reconstruction of large maxillofacial defects generally requires harvesting bone from extra-oral sites. The main source of autogenous bone is the iliac crest. This donor site is used to obtain bone for augmentation in orthopaedic surgery, neurosurgery, and oral and maxillofacial surgery, where the main indications are secondary and tertiary osteoplasty in patients with cleft-lip and palate, reconstruction of bony defects after operations for tumours, and augmentation of severe atrophy of the alveolar crest in preprosthetic surgery. A review of the literature on complications following bone harvesting from the anterior iliac crest reveals persistent pain, nerve injury, haemorrhage, limping, persistent gait abnormalities, conspicuous scarring, bone contour alteration, infection, fracture, meralgia paraesthetica, peritonitis, and herniation. The authors report an unusual complication: a huge iliac abscess that appeared 4 years after bimaxillary surgery involving iliac bone grafts.     

Outcome of secondary alveolar bone grafting before and after eruption of the canine in Jordanian patients with cleft lip and palate

This prospective study was carried out at the Cleft Lip and Palate Centre at King Abdullah University Hospital and Maxillofacial Unit at Jordan University of Science and Technology during the period of 2000 to 2006. The sample consisted of 77 secondary alveolar bone grafts (62 patients), which were performed according to the same standardized surgical technique by a single maxillofacial surgeon.The objective was to assess the outcome of secondary alveolar bone grafting (SABG) before (early SABG) and after (late SABG) the eruption of the permanent maxillary canine in unilateral and bilateral Jordanian cleft subjects. Patients were divided into four groups: early unilateral SABG (22), late unilateral SABG (25), early bilateral SABG (8), and late bilateral SABG (7). Follow-up period ranged from 6 months to 5 years. Periapical or occlusal radiographs were used to assess the outcome of SABG. The degree of bony fill in the cleft area was assessed using the 4-point Kindelan scale. Only Grade 1 (more than 75% bony fill) cases were considered successful. Early unilateral SABG had a success rate of 90% while late unilateral SABG rate was 80%. The overall success rate of the unilateral SABG (85%) was higher than the rate for the bilateral cases (56%). Our findings support the conclusion that the outcome of early SABG is superior to late SABG. The overall success rate of SABG sample (74%) compared relatively well with other published results.     

Low-level laser effect on neural regeneration in Gore-Tex tubes.

PURPOSE: The purpose of this investigation was to determine the effects of low-level laser (LLL) irradiation on neural regeneration in surgically created defects in the rabbit inferior alveolar nerve. STUDY DESIGN: Five adult female New Zealand White rabbits underwent bilateral exposure of the inferior alveolar nerve. A 6-mm segment of nerve was resected, and the nerve gap was repaired via entubulation by using a Gore-Tex conduit. The experimental side received 10 postoperative LLL treatments with a 70-mW gallium-aluminum-arsenide diode at 4 sites per treatment. At 15 weeks after surgery, the nerve segments were harvested bilaterally and prepared for light microscopy. Basic fuchsin and toluidine blue were used to highlight myelinated axons. The segments were examined histomorphometrically by using computer analysis to determine mean axonal diameter, total fascicular surface area, and axonal density along the repair sites. RESULTS: Gross examination of all nerves showed intact neural bundles with variable degrees of osseous remodeling. Light microscopic evaluation revealed organized regenerated neural tissue in both groups with more intrafascicular perineural tissue in the control group. Histomorphometric evaluation revealed increased axonal density in the laser treated group as compared with the control. CONCLUSIONS: LLL irradiation may be a useful noninvasive adjunct to promote neuronal wound healing in surgically created defects repaired with expanded polytetrafluoroethylene entubulation.